vulkan/wsi: Add X11 adaptive sync support based on dri options.

The dri options are optional. When the dri options are not provided
the WSI will not  use adaptive sync.

FWIW I think for xf86-video-amdgpu this still requires an X11 config
option, so only people who opt in can get possible regressions from this.

So then the remaining question is: why do this in the WSI?

It has been suggested in another MR that the application sets this.
However, I disagree with that as I don't think we'll ever get a
reasonable set of applications setting it.

The next questions is whether this can be a layer. It definitely
can be as implemented now. However, I think this generally fits
well with the function of the WSI. Furthemore, for e.g. the DISPLAY
WSI this is much harder to do in a layer.

Of course, most of the WSI could almost be a layer, but I think
this still fits best in the WSI.

Acked-by: Jason Ekstrand <[email protected]>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/vulkan/wsi/wsi_common_x11.c b/src/vulkan/wsi/wsi_common_x11.c
index 1782aa525bc..46f1c08b453 100644
--- a/src/vulkan/wsi/wsi_common_x11.c
+++ b/src/vulkan/wsi/wsi_common_x11.c
@@ -1315,6 +1315,33 @@ x11_swapchain_destroy(struct wsi_swapchain *anv_chain,
    return VK_SUCCESS;
 }
 
+static void
+wsi_x11_set_adaptive_sync_property(xcb_connection_t *conn,
+                                   xcb_drawable_t drawable,
+                                   uint32_t state)
+{
+   static char const name[] = "_VARIABLE_REFRESH";
+   xcb_intern_atom_cookie_t cookie;
+   xcb_intern_atom_reply_t* reply;
+   xcb_void_cookie_t check;
+
+   cookie = xcb_intern_atom(conn, 0, strlen(name), name);
+   reply = xcb_intern_atom_reply(conn, cookie, NULL);
+   if (reply == NULL)
+      return;
+
+   if (state)
+      check = xcb_change_property_checked(conn, XCB_PROP_MODE_REPLACE,
+                                          drawable, reply->atom,
+                                          XCB_ATOM_CARDINAL, 32, 1, &state);
+   else
+      check = xcb_delete_property_checked(conn, drawable, reply->atom);
+
+   xcb_discard_reply(conn, check.sequence);
+   free(reply);
+}
+
+
 static VkResult
 x11_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
                              VkDevice device,
@@ -1467,6 +1494,13 @@ x11_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
 
    for (int i = 0; i < ARRAY_SIZE(modifiers); i++)
       vk_free(pAllocator, modifiers[i]);
+
+   /* It is safe to set it here as only one swapchain can be associated with
+    * the window, and swapchain creation does the association. At this point
+    * we know the creation is going to succeed. */
+   wsi_x11_set_adaptive_sync_property(conn, window,
+                                      wsi_device->enable_adaptive_sync);
+
    *swapchain_out = &chain->base;
 
    return VK_SUCCESS;